Fig. 11

a Well-defined fusiform hypoechoic lesion (white arrowheads) is noted in continuity of the superficial branch of the radial nerve in the region of the anatomical snuffbox, just distal to the radial styloid. b T1-weighted coronal image shows another well-defined, T1 hypointense, fusiform lesion (white arrowhead) in continuity with the superficial branch of the radial nerve at the distal end of the radius. c PD fat-saturated sequence in the sagittal plane showing multiple PD hyperintense lesions (white arrowheads) along the superficial branch of the radial nerve. The lesions were hyperintense on T2 sequence also, showing internal fascicular areas suggestive of neural origin. d Axial post-contrast fat-saturated T1 image showing well-defined hypointense lesion surrounded by an enhancing capsule (arrowhead) in continuity with the superficial branch of the radial nerve. Another similar lesion (arrow) showing heterogenous contrast enhancement with hypointense areas within can be seen in continuity with the median nerve. This lesion was T2 and PD hyperintense with cystic degenerative changes on ultrasound and MRI. These MR findings fit the description of ancient schwannomas [33]. Ultrasound is a preliminary tool for identifying PNSTs, but MRI is the modality of choice as it helps in differentiating between neuromas and PNSTs